Re: Backtrace in rds code
From: David Miller <davem@davemloft.net>
Date: 2012-01-24 22:04:17
Subsystem:
networking [general], rds - reliable datagram sockets, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Allison Henderson, Linus Torvalds
Please try this patch: -------------------- rds: Make rds_sock_lock BH rather than IRQ safe. rds_sock_info() triggers locking warnings because we try to perform a local_bh_enable() (via sock_i_ino()) while hardware interrupts are disabled (via taking rds_sock_lock). There is no reason for rds_sock_lock to be a hardware IRQ disabling lock, none of these access paths run in hardware interrupt context. Therefore making it a BH disabling lock is safe and sufficient to fix this bug. Reported-by: Kumar Sanghvi <redacted> Reported-by: Josh Boyer <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/rds/af_rds.c | 20 ++++++++------------ 1 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index bb6ad81..424ff62 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c@@ -68,7 +68,6 @@ static int rds_release(struct socket *sock) { struct sock *sk = sock->sk; struct rds_sock *rs; - unsigned long flags; if (!sk) goto out;
@@ -94,10 +93,10 @@ static int rds_release(struct socket *sock) rds_rdma_drop_keys(rs); rds_notify_queue_get(rs, NULL); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_del_init(&rs->rs_item); rds_sock_count--; - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); rds_trans_put(rs->rs_transport);
@@ -409,7 +408,6 @@ static const struct proto_ops rds_proto_ops = { static int __rds_create(struct socket *sock, struct sock *sk, int protocol) { - unsigned long flags; struct rds_sock *rs; sock_init_data(sock, sk);
@@ -426,10 +424,10 @@ static int __rds_create(struct socket *sock, struct sock *sk, int protocol) spin_lock_init(&rs->rs_rdma_lock); rs->rs_rdma_keys = RB_ROOT; - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_add_tail(&rs->rs_item, &rds_sock_list); rds_sock_count++; - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); return 0; }
@@ -471,12 +469,11 @@ static void rds_sock_inc_info(struct socket *sock, unsigned int len, { struct rds_sock *rs; struct rds_incoming *inc; - unsigned long flags; unsigned int total = 0; len /= sizeof(struct rds_info_message); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); list_for_each_entry(rs, &rds_sock_list, rs_item) { read_lock(&rs->rs_recv_lock);
@@ -492,7 +489,7 @@ static void rds_sock_inc_info(struct socket *sock, unsigned int len, read_unlock(&rs->rs_recv_lock); } - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); lens->nr = total; lens->each = sizeof(struct rds_info_message);
@@ -504,11 +501,10 @@ static void rds_sock_info(struct socket *sock, unsigned int len, { struct rds_info_socket sinfo; struct rds_sock *rs; - unsigned long flags; len /= sizeof(struct rds_info_socket); - spin_lock_irqsave(&rds_sock_lock, flags); + spin_lock_bh(&rds_sock_lock); if (len < rds_sock_count) goto out;
@@ -529,7 +525,7 @@ out: lens->nr = rds_sock_count; lens->each = sizeof(struct rds_info_socket); - spin_unlock_irqrestore(&rds_sock_lock, flags); + spin_unlock_bh(&rds_sock_lock); } static void rds_exit(void)
--
1.7.7.6